Sir,
I can see all the features you have explained here, except that i am not sure about lower glumes. I assume that those triangular shapes, with lighter shades, at the bases of spikelets (pic no. grass19jul12_BB_DSCN7401.jpg) are lower glumes.
And, as you have mentioned, i found this grass in a shady place, under a Arjuna and a Tamarind tree.
Regards,
surajit